problem with load assembly

I have a problem with load assembly. I have two solutions. The first solution, which name is Studio want load and use second solution, which name is Worker. Type of Worker solution is class library. Worker solution use some outsider assemblys, which names
is Ecng.Common, Ecng.Data, etc. . When i try to load Worker solution in Studio solution by MEF, MEF throw exception, that say, that he can't find file or assemble Ecng.Transactions. But this assembly don't using in Worker solution. Worker solution work without
it. What i need to do? Sorry about my english, it is't very good.